Someone who claims to be a goth/punk/skater/grunger/whatever without knowing what it is they're trying to become. Anyone who says they do Witchcraft and threatens to cast a spell on you (the rule says: don't threaten, don't warn). Anyone doing anything just to look cool. (Most "punks")

Avril Lavigne was going to do Country music until she was told she wouldn't be sign if she didn't do a "punk act", oh wait, she's not just a poser, she's a sell-out, too.

Any one who does not follow his/her own ideas of what he/she likes. Following no one set norm makes you real and following no one set norm makes you poser. Poser is governed not by the clothes, music, or makeup you wear, but rather by the state of your mind and the conformity to your own beliefs.

a person - usually in middle or high school, who is insecure about him/herself and trys very hard not to be a "conformist" or a "prep," by doing things like: purchasing a skateboard or guitar, purchasing a great deal of clothing and accessories from hot topic, and listening to pop-punk bands such as simple plan, yellowcard, etc. usually, this supposedly "nonconformist" behavior just backfires on him/her, because now he/she is still conforming, just to a different group of people. so the moral of the story is to be yourself.

Someone whos acts like someone theyre not,but not realizing that there being fake, basically a loser trying to fit in.

A poser green day fan,this applies to other poser bands--
Todd:have you heard american idiot?Thats the bestest song ever!
Bill:Have u even heard any other green day songs?
Todd:what other green day songs?

A poser is someone who tries hard to be something they arent. Usually, posers call other people posers because they are jealous that the person they called a poser is more skater/stoner/goth/punk/rocker/grunge/etc. than they will ever be.